- Arm I: Patients undergo radiotherapy daily 5 days a week over 7 weeks for a total of 34 fractions. Patients also receive chemotherapy comprising O6-benzylguanine IV over 1 hour followed 6 hours later by carmustine IV over 1 hour on day 1 of radiotherapy. Chemotherapy repeats every 6 weeks for a maximum of 7 courses in the absence of disease progression or unacceptable toxicity.